Gadamer’s engagement with Heidegger’s philosophical legacy consists of two seemingly contradictory elements. On the one hand, he views himself as committed to Heidegger’s critique of the history of philosophical thought under the thesis of the «forgetfulness of Being» in metaphysics. On the other hand, he seeks to take a critical distance from the claim regarding the «end of philosophy». The affirmative dimension of his demarcation from certain claims of the later Heidegger is grounded in the establishment of a linguistically-constituted ontology based on the claim of the universality of philosophical hermeneutics. The fundamental question before us is: upon what foundation must this ontology rest so that it can simultaneously avoid a return to the tenets of metaphysical thought, and provide a different framework from Heidegger for the question of Being? To investigate this issue, we first examine the later Heidegger’s conception of the nature of metaphysics. Then, we provide an extended re-reading of Gadamer's view on the nature of linguistically-constituted ontology; on this basis, the question of the origin and source of linguisticality is considered the very component upon which Gadamer's success or failure in providing an answer depends. In the final step, we introduce the principles of the «One» and the «Indeterminate Dyad» as an alternative to Heidegger's ontological difference, demonstrating how these principles justify the problem of the source of linguisticality in philosophical hermeneutics. Consequently, they provide the possibility of realizing Gadamer's claim concerning the preservation of a dialogical relationship with the philosophical tradition, while avoiding the reproduction of metaphysics.